Observations of Local Meteorological Variability under Large-Scale Circulation Patterns over Athens, Greece

Christos Halios,Panagiotis Mouschouras,Helena Flocas,Dimosthenis Asimakopoulos,Costas Helmis

doi:10.3390/atmos9010025

Abstract

Linking synoptic circulation patterns to specific environmental problems is of significance in the Eastern Mediterranean region, which is characterized by increased seasonal climatic variability and a wealth of distinct weather patterns. This study aims to discuss the links between synoptic scale circulation, intra-day variability and sub-hourly temperature changes over Athens. Diurnal cycles of surface atmospheric variability were examined by applying Principal Component Analysis and Integral Quantities Analysis to a four months data set with surface meteorological elements. Sub-hourly temperature changes were identified by applying a simple linear technique. Principal Components, Integral Quantities and temperature change rates (geometric structures) were related with synoptic circulation categories. It was found that the presence of a Closed Low over the area results in intense along-mountain flows, whilst, after the passage of a trough, when a strong northwesterly flow is established over the area, surface recirculation flows develop. On 64% of the days, geometric structures were observed in the hourly temperature time-series, and they were found to occur across all synoptic situations. Cliff—ramps was the most common geometric structure, and step changes were found to be related with recirculation flows.

Highlights

It is widely recognized that we live in an era when technological innovation allows the integration of different sources of information in advanced predictive tools that will provide seamless prediction engaging atmospheric processes of a wide range of temporal and spatial scales [1]
In [8], the aim was to tackle the links between synoptic scale circulation and mesoscale surface variability on a daily basis, the focus of the present study is to extend the examination to a wider range of scales by discussing the links between synoptic scale circulation, intra-day variability and sub-hourly temperature changes
Diurnal cycles of atmospheric variability and sub-hourly temperature changes in the form of geometric structures were linked with synoptic scale circulation categories

Summary

Introduction

It is widely recognized that we live in an era when technological innovation allows the integration of different sources of information in advanced predictive tools that will provide seamless prediction engaging atmospheric processes of a wide range of temporal and spatial scales [1]. Understanding the interactions between these scales is critical for the design of future parametrizations and observation networks [2]. In this context, tackling the interactions between large-scale atmospheric circulation and local scale meteorology, which characterizes the climate of a region, is significant. The linkage of atmospheric circulation and environmental response can be approached either with a circulation to environment or an environment to circulation perspective [10].

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Conclusion